Myocardial Infarction - Johnston Flashcards Preview

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Flashcards in Myocardial Infarction - Johnston Deck (44):
1

Inverted T waves

Where usually?

Ischemia
- Chest leads (closest to ventricles)

2

Causes of MI (occlusion)

- Atherosclerosis
- Vasospasm
- Vasculitis
- Dissection
- Genetics

3

Chest pain, etc. not relieved by nitro or rest...Think what?

MI

4

Silent MI...think what?

Diabetics, elderly women

5

4 signs of new heart failure

- S3 gallop
- Crackles in lungs
- Increased JVD
- New murmur

6

Autonomic responses for...

Anterior MI vs. Inferior MI

Anterior - sympathetic (tachy, HTN)

Inferior - parasympathetic (bradycardia, hypotension)

7

EKG signs of STEMI

- Men - > 2mm STE (V2-V3)
- Women - > 1.5mm STE (2 or more contiguous leads)
- Maybe new LBBB

8

NSTEMI or NST ACS - EKG

ST depression, T wave inversion

9

Distinguishing NSTEMI from NSTE ACS

NSTEMI - elevated cardiac enzymes
NSTE ACS (angina) - normal cardiac enzymes

10

Early phase of STEMI - EKG

What are they?

Tall hyperacute T waves
- Upward, slightly curved pattern

11

Causes of inverted T waves (7)

- Normal in children (V1-3)
- Myocardial ischemia
- BBB
- Ventricular hyper. w/ strain
- P.E.
- Hypertrophic cardiomy.
- Raised ICP

12

How to tell where the acute MI is occurring?

Where are the inverted T waves?
- Inferior = 2, 3, F
- Lateral = 1, L, V5-6
- Anterior = V2-6

13

ANY T-wave inversion in leads _____ is considered pathological

V2-V6

14

Other causes of STE?

- Pericarditis
- LVH w/ J point elevation
- Normal variant early repol.

15

Pericarditis - EKG

ST segment elevation, usually flat or slightly concave, with potentially the whole T wave elevated to the next P wave

16

Causes of ST depression?

- Subendocardial ischemia
- Stress test
- Digitalis toxicity

17

Diagnostic feature for infarction on EKG

Significant Q waves (NECROSIS) in the infarcted area leads

18

What is a "significant" Q wave?

> 1mm wide or 1/3 the QRS amplitude tall

19

A normal Q wave in leads ___ is INSIGNIFICANT

AVR, V5-6

20

SO, 3 things to look for when suspecting MI?

- Significant Q waves
- STE or ST depression
- Inverted T waves

21

Describe why a Q wave means necrosis?

If the cardiac tissue under the lead is necrotic, there is no electrical activity, so the lead picks up the septal impulse moving away towards the other ventricle

22

ST elevation in terms of MI means what?

ACUTE

23

How to detect an acute posterior infarction?

The OPPOSITE is true of that in an ANTERIOR MI...
- in V1-2, QRS is "flipped"
- in V1-2, R wave is up
- "STE" --> ST depression

24

Significant Q in 1 and AVL

Lateral MI

25

Significant Q in V1-V4

Anterior MI

26

Significant Q in 2, 3, F

Inferior MI

27

Large R in V1, V2
Mirror test

Posterior MI

28

Signs of MI can be obscured by ____

LBBB

29

Persistent ST elevation (over 2 weeks)

Ventricular aneurysm (after an MI)

30

Standard care for STEMI

- EKG and continuous cardiac monitoring
- IVs inserted
- Cardiac enzymes, blood panels, clotting times
- Reperfusion, fibrinolysis
- Heparin, MONA

31

How to monitor reperfusion therapy?

Must see resolving ST elevation within 1-2 hours

32

Major risk factor for fibrinolytic therapy

Intracranial hemorrhage

33

Good times to use fibrinolysis

STEMI or new LBBB (within 12 hours)

34

When to use a beta blocker in heart failure or MI?

If BP or HR are elevated due to compensatory response

35

When to use an ACEI in HF or MI?

If EF is low or BP is high

36

Previous Hx of MI, now hurts to breathe and feels better leaning forward

Treatment?

Dressler syndrome (immune-mediated)

Aspirin, NSAID

37

Previous MI --> fibrinolytic therapy --> ventricular tachycardia

Accelerated idioventricular rhythm (AIVR)

38

Arrhythmias associated w/ inferior MI

Sinus bradycardia, Wenckebach AV block

39

Differential diagnosis for a STEMI

- Pericarditis
- Myocarditis
- Takotsubo (stress-induced) syndrome
- Early repolarization

40

Initial pharma treatments for STEMI

- Aspirin (unless contraindicated)
- IV Heparin or antiplatelet agent

41

Full pharma list of treatments for STEMI

- Nitro
- Oxygen
- Morphine
- Aspirin
- BB - IF high BP or high HR
- Stool softener
- ACEI - IF low EF or high BP
- Thrombolytic therapy

42

Most common rhythm disturbances after an MI

V tach
V fib

43

What can occur on EKG after fibrinolytic therapy? Serious?

Slow V tach (60-100)
Benign

44

Most common cause of death after MI

Heart failure